Problem Diagram

After attempting to form a workers' union with his shipmates, a seaman is forced to walk the plank for mutiny. The moment generated at the base of the plank depends on the man's weight, his location, and the angle of the boat.

What is known:

  • The man has a weight of W lb and is standing a distance of x ft from the base of the plank.
  • The boat is tilted an angle of α, measured in degrees.



What is the moment generated about point A, which is located at the base of the plank?


  • Determine the perpendicular distance from point A to the line of action of the force as a function of x and α.
  • Calculate the moment about point A by multiplying the force times the perpendicular distance.